1. Technical Field of the Invention
The present invention relates to a flexible substrate, an electro-optical device, and an electronic device.
2. Description of the Related Art
Hitherto, as display devices for various electronic devices, electro-optical devices typified by liquid crystal display devices and EL (electroluminescence) display devices have been in widespread use. As this type of electro-optical device, there is a known arrangement wherein an IC chip which produces signals for driving an electro-optical substance such as a liquid crystal or an EL element is mounted, by the COG (chip on glass) mount technique, on a panel substrate which holds the above-mentioned electro-optical substance. Furthermore, in order to address the increase in the number of electrodes attendant upon the advance of higher definition displays, an arrangement wherein a plurality of IC chips is mounted on panel substrates, has also been proposed.
FIG. 10 is a perspective view illustrating the configuration of an electro-optical device (a liquid crystal device in this case) having a plurality of chips. As shown in the figure, this electro-optical device is configured so that a first panel substrate 81 and a second panel substrate 82 wherein electrodes are formed between the opposite surfaces thereof, are adhered together with a seal material 83 interposed therebetween, and that an electro-optical substance (a liquid crystal) is sealed between the two substrates. The first panel substrate 81 has a projecting area 81a which projects with respect to the second panel substrate 82, and a first driver IC 84 for providing a driving signal to the electrode on the first panel substrate 81 is mounted in the area 81a. Likewise, the second panel substrate 82 has a projecting area 82a which projects with respect to the first panel substrate 81, and a second driver IC 85 for providing a driving signal to the electrode on the second panel substrate 82 is mounted in the area 82a. 
However, when the arrangement shown in FIG. 10 is adopted, both of the two panel substrates have a projecting area (81a or 82a) which projects on one side with respect to the other panel substrate, so that a problem arises in that the shape of the picture-frame like region in the above-described electro-optical device, that is, the shape of the area outside the seal material 83, is not bilaterally symmetrical in either the X direction or the Y direction. In contrast, the enclosure of an electronic device such as a portable telephone generally has a bilaterally symmetrical shape. This raises a problem that the electronic device in each of the conventional electro-optical devices has inferior properties for being incorporated into the enclosure.
The present invention has been developed in light of the above-described problems, and it is an object of the present invention to provide an electro-optical device allowing the shape of the picture-frame like region to be symmetrical, an electronic device having this electro-optical device, and a flexible substrate used therein.
To solve the above-described problems, the present invention provides a flexible substrate bonded to an electro-optical panel in which a first driver IC is mounted in the area which includes one side of a panel substrate. This flexible substrate comprises a base material wherein the edge portion thereof is bonded to the vicinity of the one side of the panel substrate; a second driver IC mounted on the surface of the base material; and driver-controlling electronic components which are mounted on the same surface as the second driver IC in the base material, and which produce control signals to be provided to the first and second driver ICs.
According to this flexible substrate, the first driver IC is mounted on the panel substrate while the second driver IC is mounted on the base material. It is unnecessary, therefore, to mount the second driver IC, for example, in the vicinity of the side adjacent to one side on the first driver IC side in the panel substrate, and hence, the shape of the picture-frame like region in the electro-optical device can be made symmetrical with respect to the symmetrical axis in the direction perpendicular to the above-mentioned one side. Furthermore, since the second driver IC and the driver-controlling electronic components are mounted on the same surface in the base material, the processes of mounting these components can be facilitated.
Also, to solve the above-described problems, the present invention provides a flexible substrate bonded to an electro-optical panel in which a first driver IC is mounted in the area which includes one side of a panel substrate. This flexible substrate comprises a base material wherein the edge portion thereof is bonded to the vicinity of the one side of the panel substrate; a second driver IC mounted on the surface of the base material; and driver-controlling electronic components which are mounted in the electronic component mounting area situated between the edge portion bonded to the panel substrate and the area where the second driver IC are mounted, in the base material, and which produce control signals to be provided to the first and second driver ICs.
According to this flexible substrate, as in the foregoing, the shape of the picture-frame like region in the electro-optical device can be made symmetrical. Moreover, since the electronic component mounting area is arranged to be situated between the edge portion and the second driver IC, the wiring lines routed from the above-described electronic component mounting area to the first driver IC through the edge portion, and the wiring lines routed from the electronic component mounting area to the second driver IC can be easily formed.
Furthermore, to solve the above-described problems, the present invention provides an electro-optical device. This electro-optical device comprises an electro-optical panel having a panel substrate holding an electro-optical substance, and a first driver IC mounted in the area which includes one side of the panel substrate; a base material wherein the edge portion thereof is bonded to the vicinity of the one side of the panel substrate; a second driver IC mounted on the surface of the base material; and driver-controlling electronic components which are mounted on the same surface as the second driver in the base material, and which produce control signals to be provided to the first and second driver ICs.
According to this electro-optical device, for the same reason that was explained regarding the above-described flexible substrate, the shape of the picture-frame like region in the electro-optical device can be made symmetrical with respect to the axis in the direction perpendicular to the above-described one side. Furthermore, since the second driver IC and the driver-controlling electronic components are mounted on the same surface in the base material, the processes of mounting these on the base material can be facilitated. In addition, in this electro-optical device, if an arrangement is adopted wherein, in the base material, the driver-controlling electronic components are mounted in the electronic component mounting area situated between the edge portion bonded to the above-described panel substrate and the area where the second driver IC is mounted, the wiring lines extending out of the electronic component mounting area could be easily routed, in addition to providing the above-described effect.
Moreover, to solve the above-described problems, the present invention provides an electro-optical device. This electro-optical device comprises an electro-optical panel having a panel substrate holding an electro-optical substance, and a first driver IC mounted in the area which includes one side of the panel substrate; a base material wherein the edge portion thereof is bonded to the vicinity of the one side of the panel substrate; a second driver IC mounted on the surface of the base material; and driver-controlling electronic components, which are mounted in the electronic component mounting area situated between the edge portion bonded to the panel substrate and the area where the second driver IC are mounted, in the base material, which produce control signals to be provided to the first and second driver ICs. According to this electro-optical device, since the electronic component mounting area is disposed between the edge portion and the second driver IC, the wiring lines extending out of the electronic component mounting area could be easily routed.
Preferably, the above-described electro-optical device has an arrangement further comprising first input wiring lines which are formed on one surface of the base material, and which are used for connecting the driver-controlling electronic components to the first driver IC; and second input wiring lines which are formed on the other surface of the base material, and which are used for connecting the driver-controlling electronic components to the second driver IC. Thereby, it suffices for only one of the first and second input wiring lines to be connected to the driver-controlling electronic components through the intermediary of the base material. More specifically, if an arrangement is adopted wherein the first input wiring lines are formed on the surface opposite to the electronic components mounting area in the base material, while the second input wiring lines are formed on the same surface as the electronic components mounting area in the base material, it will suffice for only the first input wiring lines to be connected with the electronic component mounting area through the intermediary of the base material. On the other hand, the second input wiring lines could be connected to the electronic component mounting area on the same surface without the intermediary of the base material.
When the driver-controlling electronic components are electrically connected with the input wiring lines formed on the surface opposite to these driver-controlling electronic components, it is preferable that the connection therebetween be established via through holes formed in the electronic component mounting area in the base material. Moreover, it is preferable that the through holes be formed in the land areas to which the terminals of the driver-controlling electronic components are connected. This eliminates the necessity to form through holes in the midway portions of the wiring lines (i.e., portions other than the lands), thereby allowing the distance between wiring lines to be reduced.
Furthermore, to solve the above-described problems, the electronic device according to the present invention has the above-described electro-optical device as a display portion. As described above, since the electro-optical device according to the present invention is arranged so that the shape of the picture-frame like region thereof is symmetrical with respect to a particular axis, it is suitable especially for an electronic device having an enclosure which is formed symmetrically with respect to the particular axis, as an enclosure for accommodating this electro-optical device.